Late Monday, officials confirmed what family and friends feared when authorities found four bodies in wreckage strewn across nearly 3 acres of fog-covered farmland southeast of the airport here.

Donald Horan, 46, a licensed pilot and businessman known for donating generously to his church and the state's Catholic archdiocese, and his wife, Barbara, 44, were killed.

They had four daughters, now in their teens and 20s.

The crash also killed Stephen Butz, 45, and his wife, Denise, 42. They had two teenage sons.

"They leave behind six beautiful children who are hurting and grieving over the loss of their parents," Brian Wenning, a friend of the families, said Monday at a news conference.

The two men went to the same grade school together. They worshipped together at St. Mary Catholic Church. Their families vacationed together. They coached their children's sports teams together.

The two couples had spent the weekend in Destin, Fla., on the Gulf of Mexico where the Horans owned a five-bedroom home.

They flew to Florida from here Friday evening. Three other Greensburg, Ind., couples, including Donald's brother, Tom Horan, and his wife, Suzanne, also flew to Florida in a separate plane, piloted by Todd Reed of Greensburg.

The two planes departed Florida on Sunday afternoon, and encountered a thick blanket of fog as they approached their small, home airport.

The National Transportation Safety Board is heading the investigation, which is likely to include a focus on weather conditions Sunday.

"The conditions that night were horrible," said Jon Dooley, vice president of the Greensburg Board of Aviation Commissioners. "It was such that an aircraft wouldn't have seen the runway unless they were very close."

Dooley said Reed tried to land at the airport before Horan's plane arrived about 45 minutes later.

But Reed missed his approach, Dooley said. He said that normally means the pilot couldn't see the runway. The plane diverted to the airport in Columbus, Ind., a larger, better-equipped facility with a tower about 30 miles southwest. It landed safely.

Horan's plane continued on to the Greensburg airport.

The weather at that time "would have been similar or, if anything, even worse" than when Reed decided to divert to Columbus, Dooley said.

Horan, who earlier this year earned an instrument rating that allowed him to fly at night and in low-visibility situations, had bought the plane he was flying in October, Dooley said.

Greensburg Police Detective William Meyerrose said federal crash investigators were expected to examine the crash site Tuesday. He said it would be up to them to determine why the plane went down.

Meyerrose declined to say whether it's believed weather was a factor.

But Capt. Lindsay Shipps, a spokeswoman for the Civil Air Patrol, said it was so foggy Sunday night that weather conditions kept searchers grounded as they looked for wreckage.

The fog was dense across the state that night and only pilots such as Horan, licensed for instrument-only flying, could take off and land at airports, she said.

As federal investigators headed to the crash Monday afternoon, those who knew the victims shared stories of generosity and kindness - and loss.

Childhood friend Mark Burkert said the Horans would host get-togethers at their house, not just for family friends but virtually for everyone.

"You never know who you're going to meet over there, from some highly influential people to common people," Burkert said. "He was always willing to have people over. Don never met a stranger."

Burkert also said he never saw Horan and Butz without smiles on their faces.

"He could be having the worst day of his life," Burkert said of Horan, "and you would never know it."

Mark Schabel, the chief executive of the Greensburg company that Horan founded, Receivables Management Partners, said Horan loved to fly and often took his friends on trips.

Horan had bought the Piper so he could fly at night, Schabel said.

In 2007, Horan stepped down from day-to-day involvement at the company, which provides account and billing services to businesses involved in the health-care industry.

That gave Horan more time to support Catholic causes, including for the Archdiocese of Indianapolis. His philanthropy also extended to his home parish, which he supported with a sizable contribution to the new St. Mary Catholic School here.

"Don is a fantastic guy," said Paul Walston, 84, who lived near the Horans. "His whole family is great."

Greg Otolski, a spokesman for the Archdiocese of Indianapolis, confirmed Horan's generous contributions to the St. Mary Catholic School and other church causes.

"A year ago, St. Mary's Catholic School in Greensburg built a new school, probably an $8 million project," Otolski said. "I don't know how much specifically Don contributed to that, but he and his wife were significant donors and actively involved with efforts to raise funds there."

The archdiocese's auxiliary bishop, Christopher J. Coyne, said the Horans "have been very active in serving their parish and the greater archdiocese over the years."

"They traveled to every corner of the archdiocese to raise funds for ministry needs," Coyne said.

Horan also was a member of the board of directors of the Catholic Community Foundation and served as president of the foundation in 2011. The foundation oversees 407 endowments with nearly $138 million in assets.